Do webworms adjust their metabolism profiles to match what they eat?
diets induction.JPG (99570 bytes)

The matching that we detected was based entirely on webworm offspring fed a uniform diet.  That is to say that they all experienced the same environment during development.   Consequently, the variation among larvae in detoxification capacity was presumably genetic.  These genetic differences might be irrelevant, however, if larvae can adjust metabolism of each furanocoumarin to match what they consume.

To test that possibility, we concocted two artificial diets that were quite different from what they encounter in plants and also quite different from each other.  Diet 1 lacked isopimpinellin and sphondin, and Diet 2 had much more isopimpinellin and sphondin and much less xanthotoxin than plant tissue.

Would feeding on these diets cause webworms change their metabolism profiles accordingly?

The answer is no.  Although Diet 1 significantly induced metabolism of all furanocoumarins to a higher level than did Diet 2, the profile of metabolism was neither altered nor adjusted to match what was being eaten.   Metabolism profiles appear to be genetically fixed. dietmet.GIF (10503 bytes)